Geographic Range

Callithrix pygmaea, known as the pygmy marmoset, is a New World monkey species native to Bolivia, Brazil, Colombia, Ecuador, and Peru. Its range stretches across the Andean foothills of southern Colombia and southeastern Peru, and reaches eastward through northern Bolivia and into the Amazon Basin of Brazil. The taxon is divided into two subspecies: Callithrix pygmaea niveiventris and Callithrix pygmaea pygmaea. Eastern pygmy marmosets, C. p. niveiventris, are restricted by the Rio Solimões, the Rio Purus, the Rio Madeira, and the Andes. Western pygmy marmosets (C. p. pygmaea) are found between the Rio Solimões and Rio Caquetá. (Cawthon Lang, 2005; de la Torre and Rylands, 2011; Cawthon Lang, 2005; de la Torre and Rylands, 2011)

Physical Description

Pygmy marmosets are the smallest extant monkeys, with an average body length of 13 cm. A coat of buff and grey fur is marked by yellow, green, and/or black ticking on the head and back. Infants initially have grey heads and yellow coats covered with black ticking, but exhibit the adult pattern within the first month of life. Though pygmy marmosets are not considered sexually dimorphic, females may be slightly heavier than males. Longer hair around the face and neck gives C. pygmaea the appearance of a lion-like mane. Their hindlimbs are longer than their forelimbs, and their digits have claws known as tegulae. The halluces are an exception, as they possess flat nails known as ungulae. The average adult tail, typically marked with black bands, has a length of approximately 20 cm. Pygmy marmoset incisors are elongated and sharp, a likely adaptation to their diet of gums and sap. The similar eastern and western subspecies are difficult to differentiate, but sometimes exhibit dissimilar ventral hair color. ("Great Apes & Other Primates: Pygmy Marmosets", 2012; Cawthon Lang, 2005; De Magalhaes and Costa, 2009)

Reproduction

Groups of C. pygmaea often consist of 2 to 6 individuals, commonly an adult male and female with their offspring. Pygmy marmosets are generally regarded as monogamous; dominant males have even been observed aggressively maintaining exclusive access to reproductive females. Polyandry has been observed, however, in groups with multiple males. Females do not exhibit outward visible signs of ovulation, but studies of wild pygmy marmosets have suggested that females may communicate their reproductive state to males via olfactory cues and/or behavior. No correlation has been observed in pygmy marmosets between number of adult males and number of offspring. ("Great Apes & Other Primates: Pygmy Marmosets", 2012; Converse, et al., 1995; Heymann and Soini, 1999; Soini, 1987)

Female pygmy marmosets may give birth to 1 to 3 offspring, but most frequently give birth to fraternal twins. Approximately 3 weeks after giving birth, females enter a postpartum estrus during which mating occurs. With a gestation period of about 4.5 months, this system produces on average a set of twins from the dominant male and dominant female every 5 to 6 months. Pygmy marmosets have an extremely cooperative system of infant care, and only one dominant female per group produces offspring. Newborn pygmy marmosets weigh approximately 16 g. After nursing for approximately 3 months and reaching sexual maturity within a year to a year and a half, they reach their adult weight around age 2. Juveniles typically remain with their group until two subsequent birth cycles have passed. Callithrix pygmaea is the only callitrichine known to exhibit, in a sexual context, genital presenting among females and tongue protrusion and vibrating among males. ("Great Apes & Other Primates: Pygmy Marmosets", 2012; Converse, et al., 1995; De Magalhaes and Costa, 2009; Heymann and Soini, 1999; Soini, 1987)

Pygmy marmosets, like most callitrichines, are well known for sharing their parental duties. The father, the siblings of the new offspring, and even unrelated male group members have been observed carrying, grooming, and providing food for newborns. In fact, following the new offspring’s first 24 hours, the father and siblings become more and more responsible for carrying all of the young as time progresses, perhaps to relieve the stress of twins on the mother. In a study observing six groups of captive pygmy marmosets, the father did the vast majority of the carrying in 5 of the groups within 4 weeks after birth. Maternal duties were limited to nursing, anogenital licking, and protective retrieval in threatening situations—newborn pygmy marmosets begin gaining independence away from caretakers around three weeks of age, though on average they are not weaned until 3 months of age. ("Great Apes & Other Primates: Pygmy Marmosets", 2012; Wamboldt, et al., 1988)

Behavior

Callithrix pygamaeus has an arboreal and diurnal lifestyle. Individuals are known to groom each other, likely as a form of bonding. While such docile and friendly interactions are commonly observed, pygmy marmosets are also very territorial, using scent glands to mark territories of up to 100 acres in area. Pygmy marmosets choose sleeping sites proximate to their feeding source at the time, and all group members awake and exit shortly after sunrise. Social activities are prominent between two feeding peaks—one after waking up, and the other in the late afternoon that leads into retirement to the sleeping site. Studies of wild pygmy marmosets in Bolivia suggest that they prefer clinging to vertical strata with their sharp claws while feeding, whereas quadrupedalism appears to be the preferred form of locomotion for travel. ("Great Apes & Other Primates: Pygmy Marmosets", 2012; Cawthon Lang, 2005; Jackson, 2011)

Home Range

Communication and Perception

Pygmy marmosets communicate via visual cues, scents, and vocalizations. White markings on the cheeks and a vertical stripe on the nose likely facilitate visual communication. Pygmy marmosets use scents to mark areas ranging from 25 to 100 acres. To the human ear, pygmy marmoset vocalizations resemble bird calls, and can even enter the ultrasonic spectrum. Loud, open mouth trills signal alarm, such as in the case of an encroaching predator. Squeaky, closed mouth trills are used for contact calls which allow pygmy marmosets to recognize each other. Soft twittering is a sign of submission. Studies on wild marmosets have suggested that pygmy marmosets vocalize in such a manner as to appropriate the effects of the acoustics of their locality. Further studies have shown the pygmy marmosets even alter their trills when paired with a new mate. ("Great Apes & Other Primates: Pygmy Marmosets", 2012; Cawthon Lang, 2005; Snowdon and Elowson, 1999; de la Torre and Snowdon, 2002)

Food Habits

Callithrix pygmaea is primarily a gumnivore or exudativore—it feeds mostly on the gum, sap, resin, and other exudates from trees. Specialized elongated lower incisors allow individuals to drill an almost perfectly circular hole into trees. Most groups exhibit a typical feeding pattern, as it appears that the oldest holes created by pygmy marmosets in any given tree are the lowest. They then move up the tree, creating more holes until the tree no longer yields satisfactory exudates. The group then relocates to a new primary feeding source. This species likely relies heavily on gums due to its small home range, as it would not be able to rely solely on fruit. Observation of wild pygmy marmoset populations has suggested that these exudativores do not randomly choose exudate species for feeding, nor do they simply choose the most common exudate species in their home range. Insects, particularly grasshoppers, are the most coveted source of food following exudates. Pygmy marmosets are also known to consume small lizards, some fruit, flowers, and spiders. ("Great Apes & Other Primates: Pygmy Marmosets", 2012; Cawthon Lang, 2005; Yépez, et al., 2005)

Predation

The yellow, green, and brown pelage of pygmy marmosets provides a means of camouflage in their forest habitat. Pygmy marmosets have also developed a means of communication to alarm one another of potential threats. Their small body size, however, makes them potential prey for birds of prey, small felids, and climbing snakes. (Cawthon Lang, 2005)

Ecosystem Roles

It appears that the largest role these tiny primates play in their ecosystem involves their primary feeding mechanism, so they may impact the health of trees that they are feeding on. Larger, competing callitrichines such as saddleback and mustached tamarins, which also feed on exudates, may displace groups of smaller pygmy marmosets from the tree that their home base is centered around in order to take advantage of the previously drilled holes. Excluding such interactions, contact between C. pygmaea and other primates is typically uneventful. Additionally, ants may invade pygmy marmoset exudate trees, forcing relocation. Pygmy marmosets are susceptible to the parasite Toxoplasma gondii, which is known to lead to fatal toxoplasmosis in captive groups. (Cawthon Lang, 2005; Dietz, et al., 1997)

Commensal/Parasitic Species

Toxoplasma gondii

Economic Importance for Humans: Positive

Pygmy marmosets have been popular as pets, and international trade resulted in their placement in CITES Appendix I in the late 1970s. (de la Torre and Rylands, 2011)

Economic Importance for Humans: Negative

There are no known adverse effects of C. pygmaea on humans.

Conservation Status

Callithrix pygmaea was included in CITES Appendix I in 1977-1979 as a result of international trade, but it is now listed on Appendix II. It is a species of least concern on the IUCN Red List. The species currently faces no major threats, although some local populations may suffer from habitat loss. (de la Torre and Rylands, 2011)

Other Comments

Callithrix pygmaea may also be referred to as Cebuella pygmaea. Morphological and molecular studies have fueled continued debate over whether the pygmy marmoset rightly belongs to Callithrix or Cebuella. (de la Torre and Rylands, 2011)

Contributors

Glossary

living in the southern part of the New World. In other words, Central and South America.

acoustic

uses sound to communicate

arboreal

Referring to an animal that lives in trees; tree-climbing.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

cryptic

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

diurnal

active during the day, 2. lasting for one day.

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

female parental care

parental care is carried out by females

herbivore

An animal that eats mainly plants or parts of plants.

insectivore

An animal that eats mainly insects or spiders.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

male parental care

parental care is carried out by males

monogamous

Having one mate at a time.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

pet trade

the business of buying and selling animals for people to keep in their homes as pets.

polyandrous

Referring to a mating system in which a female mates with several males during one breeding season (compare polygynous).

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

scent marks

communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

tactile

uses touch to communicate

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

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The Animal Diversity Web is an educational resource written largely by and for college students. ADW doesn't cover all species in the world, nor does it include all the latest scientific information about organisms we describe. Though we edit our accounts for accuracy, we cannot guarantee all information in those accounts. While ADW staff and contributors provide references to books and websites that we believe are reputable, we cannot necessarily endorse the contents of references beyond our control.

This material is based upon work supported by the
National Science Foundation
Grants DRL 0089283, DRL 0628151, DUE 0633095, DRL 0918590, and DUE 1122742. Additional support has come from the Marisla Foundation, UM College of Literature, Science, and the Arts, Museum of Zoology, and Information and Technology Services.